The present invention relates to a structure of an electronic instrument having operation keys for, such as a telephone terminal and a portable calculator, and a manufacturing method thereof.
Description of the Related Art
FIG. 1 is a perspective view showing a conventional structure of an electronic instrument having operation keys. As shown in FIG. 1, the conventional structure of the electronic instrument provides an upper cabinet 1 and a lower cabinet 2 both formed by resin molding, operation keys 4 in an operating section 3, and a displaying section 6. And a key sheet 5 is composed of that the operation keys 4 are connected with a resin film covering the upper surfaces of the operation keys 4 one another.
Next, a manufacturing method of the key sheet 5 is explained. FIG. 2 is a sectional view showing a first manufacturing process of the key sheet 5 at the conventional structure of the electronic instrument shown in FIG. 1. First, a resin film 7, whose printing surface 8 designated images and figures were printed on, is put between an upper die 9 having the same shape surface that the cosmetic design surfaces of the operation keys 4 have and a first lower die 10 that has the shape reversed the upper die 9 and that the thickness of the resin film 7 is offset, and pressure is applied to the upper die 9 and/or the first lower die 10, and the resin film 7 is formed. In this, the resin film 7 is made of a thermoplastic resin material such as polyester, nylon, and polycarbonate, and the thickness of the resin film 7 is 50 micrometers to 100 micrometers.
FIG. 3 is a sectional view showing a second manufacturing process of the key sheet 5 at the conventional structure of the electronic instrument shown in FIG. 1. After the first manufacturing process mentioned above, as shown in FIG. 3, the first lower die 10 is replaced by a second lower die 11 whose upper surface is the same that the bottom surfaces of the operation keys 4 have, and a filler resin 13 such as an ABS resin and polycarbonate is injected from a gate 12 formed at the second lower die 11. FIG. 4 is a sectional view showing a third manufacturing process of the key sheet 5 at the conventional structure of the electronic instrument shown in FIG. 1. As shown in FIG. 4, the space between the printing surface 8 of the resin film 7 and the second lower die 11 is filled with the filler resin 13, after the filler resin 13 was hardened, both of the upper die 9 and the second lower die 11 are removed. FIG. 5 is a sectional view of the key sheet 5 at the conventional structure of the electronic instrument. As shown in FIG. 5, the key sheet 5 with the operation keys 4 is formed.
FIG. 6 is a sectional view showing a structure of the operating part at the conventional structure of the electronic instrument. As shown in FIG. 6, the operating part at the conventional structure consists of the upper cabinet 1, the key sheet 5 with the operation keys 4, a rubber sheet 14, dome shaped switches 15, and a printed circuit board (PCB) 16.
At the operating part at the conventional structure, the reason why the rubber sheet 14 is inserted between the key sheet 5 with the operation keys 4 and the PCB 16 is to prevent the PCB 16 and the dome shaped switches 15 from being corroded by that water and/or dust enter from a gap between the upper cabinet 1 and the key sheet 5.
At the conventional structure of the electronic instrument, as shown in FIG. 6, the key sheet 5 with the operation keys 4, which was formed by that the filler resin 13 was filled under the resin film 7, is set into the opening part of the upper cabinet 1.
However, at the conventional structure of the electronic instrument, there is a possibility that water and/or dust enter the inside of the electronic instrument from the gap between the key sheet 5 with the operation keys 4 and the upper cabinet 1. Therefore, the rubber sheet 14 is inserted between the key sheet 5 with the operation keys 4 and the PCB 16 to which the dome shaped switches 15 were mounted, and the water and/or dust are prevented from entering the inside of the electronic instrument. However, the key sheet 5 with the operation keys 4 is set into the opening part of the upper cabinet 1 in the state that the key sheet 5 with the operation keys 4 only presses the PCB 16, therefore, the water and/or the dust can not be entirely prevented from entering the inside of the electronic instrument. Furthermore, the number of the components is too large, and must be reduced in order to meet that the electronic instrument is small (thin) sized and light weighted.
It is therefore an object of the present invention to provide a structure of an electronic instrument having operation keys and a manufacturing method thereof, in which a dustproof and waterproof function can be secured by a simple structure.
According to a first aspect of the present invention for achieving the object mentioned above, there is provided a structure of an electronic instrument having operation keys. The structure of the electronic instrument having operation keys provides a cabinet providing an opening part for operation keys, operation keys that are disposed in the opening part of the cabinet so that each of the operation keys is movable in the orthogonal direction to the front surface of the cabinet, and a resin film that covers the surface of the cabinet and the surfaces of the operation keys in the state that the resin film is not cut on the surfaces of the cabinet and the operation keys, and covers a gap formed between the cabinet and the operation keys, and gaps formed among the operation keys.
According to a second aspect of the present invention, in the first aspect, designated images and figures are printed on the surface contacting the cabinet and the operation keys of the resin film.
According to a third aspect of the present invention, in the first aspect, the cabinet is divided into an upper cabinet and a lower cabinet and composed of the upper cabinet and the lower cabinet, and the operation keys are disposed in an opening part of the upper cabinet, and the edge part of the resin film is extended to the part where the upper cabinet and the lower cabinet are joined.
According to a fourth aspect of the present invention, in the first aspect, the cabinet provides a displaying part and the displaying part is at least transparent, and the part of the resin film where the displaying part is disposed is transparent.
According to a fifth aspect of the present invention, in the third aspect, the upper cabinet provides a displaying part and the displaying part is at least transparent, and the part of the resin film where the displaying part is disposed is transparent.
According to a sixth aspect of the present invention, in the first aspect, a printed circuit board in which switches contacting to each of the operation keys are mounted is provided in the cabinet.
According to a seventh aspect of the present invention, there is provided a manufacturing method of an electronic instrument having operation keys. At the manufacturing method of the electronic instrument having operation keys, the electronic instrument having operation keys provides a cabinet providing an opening part for operation keys, and operation keys that are disposed in the opening part of the cabinet so that each of the operation keys is movable in the orthogonal direction to the front surface of the cabinet, and a resin film is formed on a cavity plate having concave parts being the same shape of the outer shape of the cabinet and the outer shape of the operation keys at the state that the operation keys are disposed at the designated positions in the opening part of the cabinet by using a first core plate having convex parts (the concave parts are reversed and the thickness of the resin film is reduced) being the similar figure of the concave parts of the cavity plate by applying pressure. And after this, the first core plate is replaced with a second core plate, and empty spaces are formed between the cavity plate and the second core plate, and a resin material is filled in the empty spaces, and the cabinet and the operation keys are formed by the resin material, and a gap formed between the cabinet and the operation keys is covered with the resin film, and gaps formed among the operation keys are covered with the resin film.
According to an eighth aspect of the present invention, in the seventh aspect, designated images and figures are printed on the surface contacting to the cabinet and the operation keys of the resin film before the resin film is formed on the cavity plate.
According to a ninth aspect of the present invention, in the seventh aspect, the cabinet and the operation keys are formed by an injection molding when the resin material is injected into the empty spaces.
According to a tenth aspect of the present invention, there is provided a manufacturing method of an electronic instrument having operation keys. The manufacturing method of the electronic instrument having operation keys provides the steps of; placing a cavity plate having concave parts being the same shape of the outer shape of an upper cabinet and the outer shape of operation keys at the state that the operation keys are disposed at designated positions in an opening part of the upper cabinet, placing a resin film on the inside surface of the cavity plate in the state that the resin film is extended to the edge part of the cavity plate, placing a first core plate having convex parts (the concave parts are reversed and the thickness of the resin film is reduced) being the similar figure of the concave parts of the cavity plate on the resin film, and applying pressure to the resin film in the direction of the cavity plate through the first core plate, and forming the resin film on the cavity plate, removing the first core plate, placing a second core plate in the state that the second core plate faces with the resin film with empty spaces between the resin film and the second core plate, injecting a resin material from gates of the second core plate into the empty spaces, and removing the second core plate. And the upper cabinet and the operation keys are formed by the resin material, in the state that a gap formed between the upper cabinet and the operation keys is covered with the resin film, and gaps formed among the operation keys are covered with the resin material, and in the state that the resin film is extended to the part where the upper cabinet is fixed with a lower cabinet of the electronic instrument on the surface of the upper cabinet.
According to an eleventh aspect of the present invention, in the tenth aspect, the manufacturing method of the electronic instrument having operation keys further provides the step of; printing designated images and figures on the surface contacting to the upper cabinet and the operation keys of the resin film before the resin film is formed on the cavity plate.